Monorden, 5-Chloro-6-(7,8-epoxy-10-hydroxy-2-oxo-3,5-undecadienyl)-.beta.-resorcylic acid .mu.-lactone, also known as radicicol, is an antibiotic substance isolated from several microorganisms including Monosporium bonarden: Delmotte, Delmotte-Plaquee, Nature 171, 344 (1953). The structural formula, physical, chemical, and other properties are given in the Merck Index, ninth edition, page 811, compound 6089.
The success and profit for animal breeders raising cattle, swine, sheep, goats, horses, mink, rats, mice, and many other animals depends largely upon the ability to produce large numbers of viable offspring. It is, therefore, desirable to increase the conception rate by insuring that each female is impregnated as often as possible and increase the birth rate and litter sizes by inducing multiple births from each impregnation. It is also important to promote estrus synchronization to control when offspring will be born. In the natural method, allowing two animals to mate, the female may fail to become pregnant up to 50% or more of the time and multiple births may be rare or litters may be smaller than desirable. It has been estimated that dairy farmers lose 10% of their total income because cattle fail to become impregnated on the first mating. Additionally, offspring are generally born at various times throughout the year instead of at a specific period controlled by the breeder.
Various methods have been developed to overcome these problems. Artifical insemination can improve the conception rate somewhat but generally does not increase the number of births per conception. Subsequently, methods to increase the success of artificial insemination were developed. For example, U.S. Pat. No. 4,119,089 discloses a method for predicting ovulation and therefor the best time for artifical insemination by monitoring volatile sulfur compounds in the animal's breath. These methods, however, have not been wholly successful particularly where animals that for whatever reasons are very difficult to impregnate or hold their breath.
Methods for increasing fertility in animals by stimulating and controlling ovulation have increased the conception rate. Treating animals with progesterone and other hormonal compounds can significantly increase the conception rate, but the high cost of hormonal products and the adverse side effects have prevented their widespread use. For example, U.S. Pat. Nos. 3,830,907 and 3,565,991 disclose using nortesterone compounds to control ovulation and estrus. Numerous patents, e.g. U.S. Pat. Nos. 2,379,832, 2,232,438, and 2,324,185, have related to progesterone which has been used to control habitual abortion and suppress or synchronize estrus. These compounds, however, are often expensive, difficult to handle, and have adverse side effects such as estrogenic-like changes in body weight, uterine weight, etc. in the animal.
Other compounds have also been used to increase fertility by controlling and stimulating ovulation. U.S. Pat. No. 4,283,419 discloses administering tris-(2-ethoxy-ammonium-orthocresoxy) acetate and U.S. Pat. No. 3,463,860 discloses administering para-hydroxybenzoic acid esters to increase fertility in animals. Japanese Patent No. 58043725 discloses feeding argenine and lysine to cattle to increase birth rate from approximately 50% to 83.3%. These compounds, however, generally have estrogen-type side effects chararacteristic of the analogous hormonal compounds.
An inexpensive and effective method is, therefore, needed which can increase fertility in animals by increasing the conception rate, inducing multiple births, increasing litter sizes, and promoting estrus syncronization without producing the adverse side effects characteristic of prior methods.